CVE-2021-3317:Command Injection Vulnerability in KLog Server through 2.4.1

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KLog Server through version 2.4.1 contains a command injection vulnerability that allows authenticated users to execute arbitrary commands on the underlying operating system. The vulnerability exists in the async.php file, which calls the shell_exec() function directly on the user-supplied 'source' parameter without proper validation or sanitization.

Overview

This vulnerability (CVE-2021-3317) is classified as CWE-78 (OS Command Injection). When exploited, it allows authenticated attackers to execute arbitrary system commands with the privileges of the web server process. The issue stems from improper input validation in the async.php file where the application passes user-controlled data from the 'source' parameter directly to the shell_exec() function. This dangerous implementation allows attackers to inject operating system commands that will be executed on the server hosting the KLog application.

Remediation

Organizations using KLog Server should implement the following remediation steps:

  1. Update to a patched version of KLog Server if available.
  2. If updates are not available, implement input validation for the 'source' parameter in async.php:
    • Whitelist allowed values instead of accepting arbitrary input
    • Sanitize user input by removing or escaping special characters
    • Use parameterized functions instead of shell_exec() where possible
  3. Consider implementing additional access controls to restrict who can access the vulnerable functionality.
  4. Monitor system logs for suspicious activities that might indicate exploitation attempts.
  5. Apply the principle of least privilege to the web server process to minimize the impact of potential exploitation.

References

  1. Packet Storm Security - Klog Server 2.4.1 Command Injection: http://packetstormsecurity.com/files/161208/Klog-Server-2.4.1-Command-Injection.html

  2. Unsafe-Inline Documentation - KLog Server Authenticated Command Injection: https://docs.unsafe-inline.com/0day/klog-server-authenticated-command-injection

  3. Common Weakness Enumeration - CWE-78 (OS Command Injection): https://cwe.mitre.org/data/definitions/78.html

Industry ExposureMost to least
This section illustrates the prevalence of a specific Common Vulnerabilities and Exposures (CVE) across various industries based on customer reports. The ranking displays industries from the most to least affected by this particular vulnerability, offering valuable insight into where this CVE has been most frequently observed. This information can help organizations within these sectors prioritize their security efforts, understand their relative risk exposure compared to their peers, and focus remediation strategies where they are most needed. By understanding the industry-specific impact, organizations can make more informed decisions regarding patching, resource allocation, and overall risk management related to this CVE.

  1. Accommodation & Food Services
    Accommodation & Food Services
  2. Administrative, Support, Waste Management & Remediation Services
    Administrative, Support, Waste Management & Remediation Services
  3. Agriculture, Forestry Fishing & Hunting
    Agriculture, Forestry Fishing & Hunting
  4. Arts, Entertainment & Recreation
    Arts, Entertainment & Recreation
  5. Construction
    Construction
  6. Educational Services
    Educational Services
  7. Finance and Insurance
    Finance and Insurance
  8. Health Care & Social Assistance
    Health Care & Social Assistance
  9. Information
    Information
  10. Management of Companies & Enterprises
    Management of Companies & Enterprises
  11. Manufacturing
    Manufacturing
  12. Mining
    Mining
  13. Other Services (except Public Administration)
    Other Services (except Public Administration)
  14. Professional, Scientific, & Technical Services
    Professional, Scientific, & Technical Services
  15. Public Administration
    Public Administration
  16. Real Estate Rental & Leasing
    Real Estate Rental & Leasing
  17. Retail Trade
    Retail Trade
  18. Transportation & Warehousing
    Transportation & Warehousing
  19. Utilities
    Utilities
  20. Wholesale Trade
    Wholesale Trade

Focus on What Matters

  1. See Everything.
  2. Identify True Risk.
  3. Proactively Mitigate Threats.

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